ice: Poll for link status change

When the physical link goes up or down, the driver is supposed to
receive a link status event (LSE). The driver currently has the code
to handle LSEs but there is no firmware support for this feature yet.
So this patch adds the ability for the driver to poll for link status
changes. The polling itself is done in ice_watchdog_subtask.

For namespace cleanliness, this patch also removes code that handles
LSE. This code will be reintroduced once the feature is officially
supported.

Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>